diff --git a/data/extensions/aseprite-theme/dark/sheet.png b/data/extensions/aseprite-theme/dark/sheet.png
index f92d9ebf1..26907dd68 100644
Binary files a/data/extensions/aseprite-theme/dark/sheet.png and b/data/extensions/aseprite-theme/dark/sheet.png differ
diff --git a/data/extensions/aseprite-theme/dark/theme.xml b/data/extensions/aseprite-theme/dark/theme.xml
index 47125263d..bee348711 100644
--- a/data/extensions/aseprite-theme/dark/theme.xml
+++ b/data/extensions/aseprite-theme/dark/theme.xml
@@ -325,6 +325,7 @@
         <part id="timeline_drop_frame_deco" x="252" y="120" w1="2" w2="1" w3="2" h1="3" h2="1" h3="3" />
         <part id="timeline_loop_range" x="240" y="132" w1="4" w2="4" w3="4" h1="3" h2="6" h3="3" />
         <part id="timeline_focused" x="228" y="12" w1="2" w2="8" w3="2" h1="2" h2="8" h3="2" />
+        <part id="timeline_zindex" x="272" y="122" w="6" h="6" />
         <part id="flag_normal" x="0" y="240" w="16" h="10" />
         <part id="flag_highlight" x="16" y="240" w="16" h="10" />
         <part id="drop_pixels_ok" x="176" y="176" w="7" h="8" />
@@ -446,6 +447,8 @@
         <part id="cursor_skew_ne" x="288" y="160" w="16" h="16" focusx="8" focusy="8" />
         <part id="one_win_icon" x="96" y="256" w="8" h="7" />
         <part id="multi_win_icon" x="104" y="256" w="8" h="7" />
+        <part id="spin_up" x="128" y="256" w="5" h="3" />
+        <part id="spin_down" x="128" y="259" w="5" h="3" />
     </parts>
     <styles>
         <style id="box" />
@@ -936,6 +939,9 @@
         <style id="timeline_both_links">
             <background part="timeline_both_links_active" />
         </style>
+        <style id="timeline_zindex">
+            <icon part="timeline_zindex" align="right bottom" x="0" y="-1" />
+        </style>
         <style id="timeline_gear" extends="timeline_box">
             <icon part="timeline_gear" />
             <icon part="timeline_gear_active" state="focus" />
diff --git a/data/extensions/aseprite-theme/sheet.png b/data/extensions/aseprite-theme/sheet.png
index d32ef086a..ff9712253 100644
Binary files a/data/extensions/aseprite-theme/sheet.png and b/data/extensions/aseprite-theme/sheet.png differ
diff --git a/data/extensions/aseprite-theme/theme.xml b/data/extensions/aseprite-theme/theme.xml
index f8b10730b..9efeb5b4c 100644
--- a/data/extensions/aseprite-theme/theme.xml
+++ b/data/extensions/aseprite-theme/theme.xml
@@ -321,6 +321,7 @@
         <part id="timeline_drop_frame_deco" x="252" y="120" w1="2" w2="1" w3="2" h1="3" h2="1" h3="3" />
         <part id="timeline_loop_range" x="240" y="132" w1="4" w2="4" w3="4" h1="3" h2="6" h3="3" />
         <part id="timeline_focused" x="228" y="12" w1="2" w2="8" w3="2" h1="2" h2="8" h3="2" />
+        <part id="timeline_zindex" x="272" y="122" w="6" h="6" />
         <part id="flag_normal" x="0" y="240" w="16" h="10" />
         <part id="flag_highlight" x="16" y="240" w="16" h="10" />
         <part id="drop_pixels_ok" x="176" y="176" w="7" h="8" />
@@ -442,6 +443,8 @@
         <part id="cursor_skew_ne" x="288" y="160" w="16" h="16" focusx="8" focusy="8" />
         <part id="one_win_icon" x="96" y="256" w="8" h="7" />
         <part id="multi_win_icon" x="104" y="256" w="8" h="7" />
+        <part id="spin_up" x="128" y="256" w="5" h="3" />
+        <part id="spin_down" x="128" y="259" w="5" h="3" />
     </parts>
     <styles>
         <style id="box" />
@@ -926,6 +929,9 @@
         <style id="timeline_both_links">
             <background part="timeline_both_links_active" />
         </style>
+        <style id="timeline_zindex">
+            <icon part="timeline_zindex" align="right bottom" x="0" y="-1" />
+        </style>
         <style id="timeline_gear" extends="timeline_box">
             <icon part="timeline_gear" />
             <icon part="timeline_gear_active" state="focus" />
diff --git a/data/strings/en.ini b/data/strings/en.ini
index 6bb7b3677..0fd99e448 100644
--- a/data/strings/en.ini
+++ b/data/strings/en.ini
@@ -656,6 +656,7 @@ END
 [cel_properties]
 title = Cel Properties
 opacity = Opacity:
+zindex = Z-Index:
 user_data_tooltip = User Data
 
 [color_curve_point]
diff --git a/data/widgets/cel_properties.xml b/data/widgets/cel_properties.xml
index a0900c082..3e61262bb 100644
--- a/data/widgets/cel_properties.xml
+++ b/data/widgets/cel_properties.xml
@@ -1,12 +1,20 @@
 <!-- Aseprite -->
-<!-- Copyright (C) 2020 by Igara Studio S.A. -->
+<!-- Copyright (C) 2020-2023 by Igara Studio S.A. -->
 <!-- Copyright (C) 2001-2016 by David Capello -->
 <gui>
 <window id="cel_properties" text="@.title">
-  <grid id="properties_grid" columns="3">
+  <grid id="properties_grid" columns="4">
     <label text="@.opacity" />
-    <slider min="0" max="255" id="opacity" cell_align="horizontal" width="128" />
+    <slider min="0" max="255" id="opacity" cell_align="horizontal" width="128" cell_hspan="2" />
     <button id="user_data" icon="icon_user_data" tooltip="@.user_data_tooltip" />
+
+    <label text="@.zindex" />
+    <expr id="zindex" cell_align="horizontal" width="128" />
+    <buttonset id="zindex_spin" columns="1">
+      <item icon="spin_up" />
+      <item icon="spin_down" />
+    </buttonset>
+    <boxfiller />
   </grid>
 </window>
 </gui>
diff --git a/docs/ase-file-specs.md b/docs/ase-file-specs.md
index 265d892dd..a310bdb9a 100644
--- a/docs/ase-file-specs.md
+++ b/docs/ase-file-specs.md
@@ -210,7 +210,11 @@ This chunk determine where to put a cel in the specified layer/frame.
                 1 - Linked Cel
                 2 - Compressed Image
                 3 - Compressed Tilemap
-    BYTE[7]     For future (set to zero)
+    SHORT       Z-Index
+                0 = default layer ordering
+                +N = show this cel N layers later
+                -N = show this cel N layers back
+    BYTE[5]     For future (set to zero)
     + For cel type = 0 (Raw Image Data)
       WORD      Width in pixels
       WORD      Height in pixels
diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
index ea94d5559..9a1fa5fa2 100644
--- a/src/app/CMakeLists.txt
+++ b/src/app/CMakeLists.txt
@@ -506,6 +506,7 @@ add_library(app-lib
   cmd/set_cel_frame.cpp
   cmd/set_cel_opacity.cpp
   cmd/set_cel_position.cpp
+  cmd/set_cel_zindex.cpp
   cmd/set_frame_duration.cpp
   cmd/set_grid_bounds.cpp
   cmd/set_last_point.cpp
diff --git a/src/app/cmd/set_cel_zindex.cpp b/src/app/cmd/set_cel_zindex.cpp
new file mode 100644
index 000000000..9071038f7
--- /dev/null
+++ b/src/app/cmd/set_cel_zindex.cpp
@@ -0,0 +1,52 @@
+// Aseprite
+// Copyright (C) 2023  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/cmd/set_cel_zindex.h"
+
+#include "app/doc.h"
+#include "app/doc_event.h"
+#include "doc/cel.h"
+
+namespace app {
+namespace cmd {
+
+using namespace doc;
+
+SetCelZIndex::SetCelZIndex(Cel* cel, int zindex)
+  : WithCel(cel)
+  , m_oldZIndex(cel->zIndex())
+  , m_newZIndex(zindex)
+{
+}
+
+void SetCelZIndex::onExecute()
+{
+  cel()->setZIndex(m_newZIndex);
+  cel()->incrementVersion();
+}
+
+void SetCelZIndex::onUndo()
+{
+  cel()->setZIndex(m_oldZIndex);
+  cel()->incrementVersion();
+}
+
+void SetCelZIndex::onFireNotifications()
+{
+  Cel* cel = this->cel();
+  Doc* doc = static_cast<Doc*>(cel->document());
+  DocEvent ev(doc);
+  ev.sprite(cel->sprite());
+  ev.cel(cel);
+  doc->notify_observers<DocEvent&>(&DocObserver::onCelZIndexChange, ev);
+}
+
+} // namespace cmd
+} // namespace app
diff --git a/src/app/cmd/set_cel_zindex.h b/src/app/cmd/set_cel_zindex.h
new file mode 100644
index 000000000..ca3a17f4d
--- /dev/null
+++ b/src/app/cmd/set_cel_zindex.h
@@ -0,0 +1,39 @@
+// Aseprite
+// Copyright (C) 2023  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifndef APP_CMD_SET_CEL_ZINDEX_H_INCLUDED
+#define APP_CMD_SET_CEL_ZINDEX_H_INCLUDED
+#pragma once
+
+#include "app/cmd.h"
+#include "app/cmd/with_cel.h"
+
+namespace app {
+namespace cmd {
+  using namespace doc;
+
+  class SetCelZIndex : public Cmd
+                     , public WithCel {
+  public:
+    SetCelZIndex(Cel* cel, int zindex);
+
+  protected:
+    void onExecute() override;
+    void onUndo() override;
+    void onFireNotifications() override;
+    size_t onMemSize() const override {
+      return sizeof(*this);
+    }
+
+  private:
+    int m_oldZIndex;
+    int m_newZIndex;
+  };
+
+} // namespace cmd
+} // namespace app
+
+#endif
diff --git a/src/app/color_picker.cpp b/src/app/color_picker.cpp
index 9cede8846..d780a8d35 100644
--- a/src/app/color_picker.cpp
+++ b/src/app/color_picker.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2023  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -19,6 +19,7 @@
 #include "doc/image.h"
 #include "doc/layer_tilemap.h"
 #include "doc/primitives.h"
+#include "doc/render_plan.h"
 #include "doc/sprite.h"
 #include "doc/tileset.h"
 #include "gfx/point.h"
@@ -127,9 +128,11 @@ void ColorPicker::pickColor(const Site& site,
 
     // Pick from the composed image
     case FromComposition: {
+      doc::RenderPlan plan;
+      plan.addLayer(sprite->root(), site.frame());
+
       doc::CelList cels;
-      sprite->pickCels(pos.x, pos.y, site.frame(), kOpacityThreshold,
-                       sprite->allVisibleLayers(), cels);
+      sprite->pickCels(pos, kOpacityThreshold, plan, cels);
       if (!cels.empty())
         m_layer = cels.front()->layer();
 
@@ -191,9 +194,12 @@ void ColorPicker::pickColor(const Site& site,
     }
 
     case FromFirstReferenceLayer: {
+      doc::RenderPlan plan;
+      for (doc::Layer* refLayer : sprite->allVisibleReferenceLayers())
+        plan.addLayer(refLayer, site.frame());
+
       doc::CelList cels;
-      sprite->pickCels(pos.x, pos.y, site.frame(), kOpacityThreshold,
-                       sprite->allVisibleReferenceLayers(), cels);
+      sprite->pickCels(pos, kOpacityThreshold, plan, cels);
 
       for (const Cel* cel : cels) {
         doc::color_t imageColor;
diff --git a/src/app/commands/cmd_cel_properties.cpp b/src/app/commands/cmd_cel_properties.cpp
index 13713a629..cdf8bb4b1 100644
--- a/src/app/commands/cmd_cel_properties.cpp
+++ b/src/app/commands/cmd_cel_properties.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2020-2022  Igara Studio S.A.
+// Copyright (C) 2020-2023  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -11,6 +11,7 @@
 
 #include "app/app.h"
 #include "app/cmd/set_cel_opacity.h"
+#include "app/cmd/set_cel_zindex.h"
 #include "app/cmd/set_user_data.h"
 #include "app/commands/command.h"
 #include "app/console.h"
@@ -33,6 +34,9 @@
 
 #include "cel_properties.xml.h"
 
+#include <algorithm>
+#include <limits>
+
 namespace app {
 
 using namespace ui;
@@ -49,11 +53,20 @@ public:
     , m_userDataView(Preferences::instance().cels.userDataVisibility)
   {
     opacity()->Change.connect([this]{ onStartTimer(); });
+    zindex()->Change.connect([this]{ onStartTimer(); });
     userData()->Click.connect([this]{ onToggleUserData(); });
     m_timer.Tick.connect([this]{ onCommitChange(); });
 
     m_userDataView.UserDataChange.connect([this]{ onStartTimer(); });
 
+    // TODO add to Expr widget spin flag to include these widgets in
+    //      the same Expr
+    zindexSpin()->ItemChange.connect([this]{
+      int dz = (zindexSpin()->selectedItem() == 0 ? +1: -1);
+      zindex()->setTextf("%d", zindex()->textInt() + dz);
+      onStartTimer();
+    });
+
     remapWindow();
     centerWindow();
     load_window_pos(this, "CelProperties");
@@ -99,6 +112,10 @@ private:
     return opacity()->getValue();
   }
 
+  int zindexValue() const {
+    return zindex()->textInt();
+  }
+
   int countCels(int* backgroundCount = nullptr) const {
     if (backgroundCount)
       *backgroundCount = 0;
@@ -133,7 +150,8 @@ private:
     switch (msg->type()) {
 
       case kKeyDownMessage:
-        if (opacity()->hasFocus()) {
+        if (opacity()->hasFocus() ||
+            zindex()->hasFocus()) {
           KeyScancode scancode = static_cast<KeyMessage*>(msg)->scancode();
           if (scancode == kKeyEnter ||
               scancode == kKeyEsc) {
@@ -175,11 +193,16 @@ private:
     m_timer.stop();
 
     const int newOpacity = opacityValue();
+    // Clamp z-index to the limits of the .aseprite specs
+    const int newZIndex = std::clamp<int>(zindexValue(),
+                                          std::numeric_limits<int16_t>::min(),
+                                          std::numeric_limits<int16_t>::max());
     const UserData newUserData= m_userDataView.userData();
     const int count = countCels();
 
     if ((count > 1) ||
         (count == 1 && m_cel && (newOpacity != m_cel->opacity() ||
+                                 newZIndex != m_cel->zIndex() ||
                                  newUserData != m_cel->data()->userData()))) {
       try {
         ContextWriter writer(UIContext::instance());
@@ -194,6 +217,9 @@ private:
         }
 
         Sprite* sprite = m_document->sprite();
+        bool redrawTimeline = false;
+
+        // For each unique cel (don't repeat on links)
         for (Cel* cel : sprite->uniqueCels(range.selectedFrames())) {
           if (range.contains(cel->layer())) {
             if (!cel->layer()->isBackground() && newOpacity != cel->opacity()) {
@@ -206,12 +232,25 @@ private:
               // Redraw timeline because the cel's user data/color
               // might have changed.
               if (newUserData.color() != cel->data()->userData().color()) {
-                App::instance()->timeline()->invalidate();
+                redrawTimeline = true;
               }
             }
           }
         }
 
+        // For all cels (repeat links)
+        for (Cel* cel : sprite->cels(range.selectedFrames())) {
+          if (range.contains(cel->layer())) {
+            if (newZIndex != cel->zIndex()) {
+              tx(new cmd::SetCelZIndex(cel, newZIndex));
+              redrawTimeline = true;
+            }
+          }
+        }
+
+        if (redrawTimeline)
+          App::instance()->timeline()->invalidate();
+
         tx.commit();
       }
       catch (const std::exception& e) {
@@ -253,6 +292,11 @@ private:
       updateFromCel();
   }
 
+  void onCelZIndexChange(DocEvent& ev) override {
+    if (m_cel == ev.cel())
+      updateFromCel();
+  }
+
   void onUserDataChange(DocEvent& ev) override {
      if (m_cel && m_cel->data() == ev.withUserData())
       updateFromCel();
@@ -272,6 +316,7 @@ private:
     if (count > 0) {
       if (m_cel) {
         opacity()->setValue(m_cel->opacity());
+        zindex()->setTextf("%d", m_cel->zIndex());
         color_t c = m_cel->data()->userData().color();
         m_userDataView.color()->setColor(Color::fromRgb(rgba_getr(c), rgba_getg(c), rgba_getb(c), rgba_geta(c)));
         m_userDataView.entry()->setText(m_cel->data()->userData().text());
diff --git a/src/app/doc_exporter.cpp b/src/app/doc_exporter.cpp
index 1205a0cb2..4a1b888da 100644
--- a/src/app/doc_exporter.cpp
+++ b/src/app/doc_exporter.cpp
@@ -1525,7 +1525,8 @@ void DocExporter::createDataFile(const Samples& samples,
       layer->getCels(cels);
       bool someCelWithData = false;
       for (const Cel* cel : cels) {
-        if (!cel->data()->userData().isEmpty()) {
+        if (cel->zIndex() != 0 ||
+            !cel->data()->userData().isEmpty()) {
           someCelWithData = true;
           break;
         }
@@ -1536,15 +1537,21 @@ void DocExporter::createDataFile(const Samples& samples,
 
         os << ", \"cels\": [";
         for (const Cel* cel : cels) {
-          if (!cel->data()->userData().isEmpty()) {
+          if (cel->zIndex() != 0 ||
+              !cel->data()->userData().isEmpty()) {
             if (firstCel)
               firstCel = false;
             else
               os << ", ";
 
-            os << "{ \"frame\": " << cel->frame()
-               << cel->data()->userData()
-               << " }";
+            os << "{ \"frame\": " << cel->frame();
+            if (cel->zIndex() != 0) {
+              os << ", \"zIndex\": " << cel->zIndex();
+            }
+            if (!cel->data()->userData().isEmpty()) {
+              os << cel->data()->userData();
+            }
+            os << " }";
           }
         }
         os << "]";
diff --git a/src/app/doc_observer.h b/src/app/doc_observer.h
index 5b95ed321..18a6c9ff9 100644
--- a/src/app/doc_observer.h
+++ b/src/app/doc_observer.h
@@ -65,6 +65,7 @@ namespace app {
     virtual void onCelFrameChanged(DocEvent& ev) { }
     virtual void onCelPositionChanged(DocEvent& ev) { }
     virtual void onCelOpacityChange(DocEvent& ev) { }
+    virtual void onCelZIndexChange(DocEvent& ev) { }
 
     virtual void onUserDataChange(DocEvent& ev) { }
 
diff --git a/src/app/file/ase_format.cpp b/src/app/file/ase_format.cpp
index 3ec52444c..4cc51b84d 100644
--- a/src/app/file/ase_format.cpp
+++ b/src/app/file/ase_format.cpp
@@ -986,7 +986,8 @@ static void ase_file_write_cel_chunk(FILE* f, dio::AsepriteFrameHeader* frame_he
   fputw(cel->y(), f);
   fputc(cel->opacity(), f);
   fputw(cel_type, f);
-  ase_file_write_padding(f, 7);
+  fputw(cel->zIndex(), f);
+  ase_file_write_padding(f, 5);
 
   switch (cel_type) {
 
diff --git a/src/app/render/shader_renderer.cpp b/src/app/render/shader_renderer.cpp
index 3f7c72f7c..24ea141a3 100644
--- a/src/app/render/shader_renderer.cpp
+++ b/src/app/render/shader_renderer.cpp
@@ -14,6 +14,7 @@
 
 #include "app/color_utils.h"
 #include "app/util/shader_helpers.h"
+#include "doc/render_plan.h"
 #include "os/skia/skia_surface.h"
 
 #include "include/core/SkCanvas.h"
@@ -215,21 +216,21 @@ void ShaderRenderer::renderSprite(os::Surface* dstSurface,
                       area.dst.y - area.src.y);
     canvas->scale(m_proj.scaleX(), m_proj.scaleY());
 
-    drawLayerGroup(canvas, sprite, sprite->root(), frame, area);
+    RenderPlan plan;
+    plan.addLayer(sprite->root(), frame);
+    renderPlan(canvas, sprite, plan, frame, area);
   }
   canvas->restore();
 }
 
-void ShaderRenderer::drawLayerGroup(SkCanvas* canvas,
-                                    const doc::Sprite* sprite,
-                                    const doc::LayerGroup* group,
-                                    const doc::frame_t frame,
-                                    const gfx::ClipF& area)
+void ShaderRenderer::renderPlan(SkCanvas* canvas,
+                                const doc::Sprite* sprite,
+                                const doc::RenderPlan& plan,
+                                const doc::frame_t frame,
+                                const gfx::ClipF& area)
 {
-  for (auto layer : group->layers()) {
-    // Ignore hidden layers
-    if (!layer->isVisible())
-      continue;
+  for (const Cel* cel : plan.cels()) {
+    const Layer* layer = cel->layer();
 
     switch (layer->type()) {
 
@@ -346,10 +347,7 @@ void ShaderRenderer::drawLayerGroup(SkCanvas* canvas,
       }
 
       case doc::ObjectType::LayerGroup:
-        // TODO draw a group in a sub-surface and then compose that surface
-        drawLayerGroup(canvas, sprite,
-                       static_cast<const doc::LayerGroup*>(layer),
-                       frame, area);
+        ASSERT(false);
         break;
     }
 
diff --git a/src/app/render/shader_renderer.h b/src/app/render/shader_renderer.h
index 81e90cfe2..0b3a6938f 100644
--- a/src/app/render/shader_renderer.h
+++ b/src/app/render/shader_renderer.h
@@ -18,6 +18,10 @@
 class SkCanvas;
 class SkRuntimeEffect;
 
+namespace doc {
+  class RenderPlan;
+}
+
 namespace app {
 
   // Use SkSL to compose images with Skia shaders on the CPU (with the
@@ -72,11 +76,11 @@ namespace app {
                      const doc::BlendMode blendMode) override;
 
   private:
-    void drawLayerGroup(SkCanvas* canvas,
-                        const doc::Sprite* sprite,
-                        const doc::LayerGroup* group,
-                        const doc::frame_t frame,
-                        const gfx::ClipF& area);
+    void renderPlan(SkCanvas* canvas,
+                    const doc::Sprite* sprite,
+                    const doc::RenderPlan& plan,
+                    const doc::frame_t frame,
+                    const gfx::ClipF& area);
     void drawImage(SkCanvas* canvas,
                    const doc::Image* srcImage,
                    const int x,
diff --git a/src/app/script/cel_class.cpp b/src/app/script/cel_class.cpp
index 4e944828b..976c5b37b 100644
--- a/src/app/script/cel_class.cpp
+++ b/src/app/script/cel_class.cpp
@@ -12,6 +12,7 @@
 #include "app/cmd/replace_image.h"
 #include "app/cmd/set_cel_opacity.h"
 #include "app/cmd/set_cel_position.h"
+#include "app/cmd/set_cel_zindex.h"
 #include "app/doc_api.h"
 #include "app/script/docobj.h"
 #include "app/script/engine.h"
@@ -94,6 +95,13 @@ int Cel_get_opacity(lua_State* L)
   return 1;
 }
 
+int Cel_get_zIndex(lua_State* L)
+{
+  const auto cel = get_docobj<Cel>(L, 1);
+  lua_pushinteger(L, cel->zIndex());
+  return 1;
+}
+
 int Cel_set_frame(lua_State* L)
 {
   const auto cel = get_docobj<Cel>(L, 1);
@@ -144,6 +152,15 @@ int Cel_set_opacity(lua_State* L)
   return 0;
 }
 
+int Cel_set_zIndex(lua_State* L)
+{
+  auto cel = get_docobj<Cel>(L, 1);
+  Tx tx;
+  tx(new cmd::SetCelZIndex(cel, lua_tointeger(L, 2)));
+  tx.commit();
+  return 0;
+}
+
 const luaL_Reg Cel_methods[] = {
   { "__eq", Cel_eq },
   { nullptr, nullptr }
@@ -158,6 +175,7 @@ const Property Cel_properties[] = {
   { "bounds", Cel_get_bounds, nullptr },
   { "position", Cel_get_position, Cel_set_position },
   { "opacity", Cel_get_opacity, Cel_set_opacity },
+  { "zIndex", Cel_get_zIndex, Cel_set_zIndex },
   { "color", UserData_get_color<Cel>, UserData_set_color<Cel> },
   { "data", UserData_get_text<Cel>, UserData_set_text<Cel> },
   { "properties", UserData_get_properties<Cel>, UserData_set_properties<Cel> },
diff --git a/src/app/ui/timeline/timeline.cpp b/src/app/ui/timeline/timeline.cpp
index 88d2fd338..6c46aebd3 100644
--- a/src/app/ui/timeline/timeline.cpp
+++ b/src/app/ui/timeline/timeline.cpp
@@ -2398,6 +2398,11 @@ void Timeline::drawCel(ui::Graphics* g, layer_t layerIndex, frame_t frame, Cel*
   // Draw decorators to link the activeCel with its links.
   if (data && data->activeIt != data->end)
     drawCelLinkDecorators(g, full_bounds, cel, frame, is_loosely_active, is_hover, data);
+
+  // Draw 'z' if this cel has a custom z-index (non-zero)
+  if (cel && cel->zIndex() != 0) {
+    drawPart(g, bounds, nullptr, styles.timelineZindex(), is_loosely_active, is_hover);
+  }
 }
 
 void Timeline::updateCelOverlayBounds(const Hit& hit)
diff --git a/src/app/util/cel_ops.cpp b/src/app/util/cel_ops.cpp
index e98530676..762b28e85 100644
--- a/src/app/util/cel_ops.cpp
+++ b/src/app/util/cel_ops.cpp
@@ -212,10 +212,11 @@ Cel* create_cel_copy(CmdSequence* cmds,
   }
 
   // New cel
-  std::unique_ptr<Cel> dstCel(
-    new Cel(dstFrame, ImageRef(Image::create(dstPixelFormat, dstSize.w, dstSize.h))));
+  auto dstCel = std::make_unique<Cel>(
+    dstFrame, ImageRef(Image::create(dstPixelFormat, dstSize.w, dstSize.h)));
 
   dstCel->setOpacity(srcCel->opacity());
+  dstCel->setZIndex(srcCel->zIndex());
   dstCel->data()->setUserData(srcCel->data()->userData());
 
   // Special case were we copy from a tilemap...
diff --git a/src/dio/aseprite_decoder.cpp b/src/dio/aseprite_decoder.cpp
index 8d0026a36..d74ccd1fe 100644
--- a/src/dio/aseprite_decoder.cpp
+++ b/src/dio/aseprite_decoder.cpp
@@ -831,7 +831,8 @@ doc::Cel* AsepriteDecoder::readCelChunk(doc::Sprite* sprite,
   int y = ((int16_t)read16());
   int opacity = read8();
   int cel_type = read16();
-  readPadding(7);
+  int zIndex = ((int16_t)read16());
+  readPadding(5);
 
   doc::Layer* layer = nullptr;
   if (layer_index >= 0 && layer_index < doc::layer_t(m_allLayers.size()))
@@ -868,6 +869,7 @@ doc::Cel* AsepriteDecoder::readCelChunk(doc::Sprite* sprite,
         cel = std::make_unique<doc::Cel>(frame, image);
         cel->setPosition(x, y);
         cel->setOpacity(opacity);
+        cel->setZIndex(zIndex);
       }
       break;
     }
@@ -889,6 +891,7 @@ doc::Cel* AsepriteDecoder::readCelChunk(doc::Sprite* sprite,
           cel->setPosition(x, y);
           cel->setOpacity(opacity);
         }
+        cel->setZIndex(zIndex);
       }
       else {
         // Linked cel doesn't found
@@ -909,6 +912,7 @@ doc::Cel* AsepriteDecoder::readCelChunk(doc::Sprite* sprite,
         cel = std::make_unique<doc::Cel>(frame, image);
         cel->setPosition(x, y);
         cel->setOpacity(opacity);
+        cel->setZIndex(zIndex);
       }
       break;
     }
@@ -954,6 +958,7 @@ doc::Cel* AsepriteDecoder::readCelChunk(doc::Sprite* sprite,
         cel = std::make_unique<doc::Cel>(frame, image);
         cel->setPosition(x, y);
         cel->setOpacity(opacity);
+        cel->setZIndex(zIndex);
       }
       break;
     }
diff --git a/src/doc/CMakeLists.txt b/src/doc/CMakeLists.txt
index 944458869..0c6c73d18 100644
--- a/src/doc/CMakeLists.txt
+++ b/src/doc/CMakeLists.txt
@@ -57,6 +57,7 @@ add_library(doc-lib
   playback.cpp
   primitives.cpp
   remap.cpp
+  render_plan.cpp
   rgbmap_rgb5a3.cpp
   selected_frames.cpp
   selected_layers.cpp
diff --git a/src/doc/cel.cpp b/src/doc/cel.cpp
index 89f9bb881..fa9c41154 100644
--- a/src/doc/cel.cpp
+++ b/src/doc/cel.cpp
@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2019-2020 Igara Studio S.A.
+// Copyright (c) 2019-2023 Igara Studio S.A.
 // Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -46,6 +46,7 @@ Cel* Cel::MakeCopy(const frame_t newFrame,
 
   cel->setPosition(other->position());
   cel->setOpacity(other->opacity());
+  cel->setZIndex(other->zIndex());
   return cel;
 }
 
@@ -53,7 +54,9 @@ Cel* Cel::MakeCopy(const frame_t newFrame,
 Cel* Cel::MakeLink(const frame_t newFrame,
                    const Cel* other)
 {
-  return new Cel(newFrame, other->dataRef());
+  Cel* cel = new Cel(newFrame, other->dataRef());
+  cel->setZIndex(other->zIndex());
+  return cel;
 }
 
 void Cel::setFrame(frame_t frame)
@@ -93,6 +96,11 @@ void Cel::setOpacity(int opacity)
   m_data->setOpacity(opacity);
 }
 
+void Cel::setZIndex(int zindex)
+{
+  m_zIndex = zindex;
+}
+
 Document* Cel::document() const
 {
   ASSERT(m_layer);
diff --git a/src/doc/cel.h b/src/doc/cel.h
index 12b7391e7..e064c974f 100644
--- a/src/doc/cel.h
+++ b/src/doc/cel.h
@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2019-2020 Igara Studio S.A.
+// Copyright (c) 2019-2023 Igara Studio S.A.
 // Copyright (c) 2001-2016 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -39,6 +39,7 @@ namespace doc {
     const gfx::Rect& bounds() const { return m_data->bounds(); }
     const gfx::RectF& boundsF() const { return m_data->boundsF(); }
     int opacity() const { return m_data->opacity(); }
+    int zIndex() const { return m_zIndex; }
 
     gfx::Rect imageBounds() const { return m_data->imageBounds(); }
 
@@ -62,6 +63,7 @@ namespace doc {
     void setBounds(const gfx::Rect& bounds);
     void setBoundsF(const gfx::RectF& bounds);
     void setOpacity(int opacity);
+    void setZIndex(int zindex);
 
     virtual int getMemSize() const override {
       return sizeof(Cel) + m_data->getMemSize();
@@ -76,6 +78,7 @@ namespace doc {
     LayerImage* m_layer;
     frame_t m_frame;            // Frame position
     CelDataRef m_data;
+    int m_zIndex = 0;
 
     Cel();
     DISABLE_COPYING(Cel);
diff --git a/src/doc/cel_io.cpp b/src/doc/cel_io.cpp
index 7399b5280..f1b035231 100644
--- a/src/doc/cel_io.cpp
+++ b/src/doc/cel_io.cpp
@@ -1,4 +1,5 @@
 // Aseprite Document Library
+// Copyright (c) 2023 Igara Studio S.A.
 // Copyright (c) 2001-2018 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -27,6 +28,7 @@ void write_cel(std::ostream& os, const Cel* cel)
   write32(os, cel->id());
   write16(os, cel->frame());
   write32(os, cel->dataRef()->id());
+  write16(os, uint16_t(int16_t(cel->zIndex())));
 }
 
 Cel* read_cel(std::istream& is, SubObjectsIO* subObjects, bool setId)
@@ -34,11 +36,16 @@ Cel* read_cel(std::istream& is, SubObjectsIO* subObjects, bool setId)
   ObjectId id = read32(is);
   frame_t frame(read16(is));
   ObjectId celDataId = read32(is);
+  int zIndex = int(int16_t(read16(is)));
+  if (is.eof())
+    zIndex = 0;
+
   CelDataRef celData(subObjects->getCelDataRef(celDataId));
   if (!celData)
     return nullptr;
 
-  std::unique_ptr<Cel> cel(new Cel(frame, celData));
+  auto cel = std::make_unique<Cel>(frame, celData);
+  cel->setZIndex(zIndex);
   if (setId)
     cel->setId(id);
   return cel.release();
diff --git a/src/doc/render_plan.cpp b/src/doc/render_plan.cpp
new file mode 100644
index 000000000..fdc877db5
--- /dev/null
+++ b/src/doc/render_plan.cpp
@@ -0,0 +1,92 @@
+// Aseprite Document Library
+// Copyright (c) 2023  Igara Studio S.A.
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "doc/render_plan.h"
+
+#include "doc/cel.h"
+#include "doc/layer.h"
+
+#include <algorithm>
+#include <cmath>
+
+namespace doc {
+
+RenderPlan::RenderPlan()
+{
+}
+
+void RenderPlan::addLayer(const Layer* layer,
+                          const frame_t frame)
+{
+  // We cannot add new layers after using processZIndexes()/modified
+  // m_cels array using z-indexes.
+  ASSERT(m_processZIndex == true);
+
+  // We can't read this layer
+  if (!layer->isVisible())
+    return;
+
+  switch (layer->type()) {
+
+    case ObjectType::LayerImage:
+    case ObjectType::LayerTilemap: {
+      if (Cel* cel = layer->cel(frame)) {
+        m_cels.push_back(cel);
+      }
+      break;
+    }
+
+    case ObjectType::LayerGroup: {
+      for (const auto child : static_cast<const LayerGroup*>(layer)->layers()) {
+        addLayer(child, frame);
+      }
+      break;
+    }
+
+  }
+}
+
+void RenderPlan::processZIndexes() const
+{
+  m_processZIndex = false;
+
+  // If all cels has a z-index = 0, we can just use the m_cels as it is
+  bool noZIndex = true;
+  for (int i=0; i<int(m_cels.size()); ++i) {
+    const int z = m_cels[i]->zIndex();
+    if (z != 0) {
+      noZIndex = false;
+      break;
+    }
+  }
+  if (noZIndex)
+    return;
+
+  // Order cels using its real index in the m_cels array + its z-index value
+  std::vector<std::pair<int, Cel*>> indexedCels;
+  const int n = m_cels.size();
+  indexedCels.reserve(n);
+  for (int i=0; i<n; ++i) {
+    Cel* cel = m_cels[i];
+    int z = cel->zIndex();
+    indexedCels.push_back(std::make_pair(i+z, cel));
+  }
+  std::sort(indexedCels.begin(), indexedCels.end(),
+            [](const auto& a, const auto& b){
+              return
+                (a.first < b.first) ||
+                (a.first == b.first && (a.second->zIndex() < b.second->zIndex()));
+            });
+  for (int i=0; i<n; ++i) {
+    m_cels[i] = indexedCels[i].second;
+  }
+}
+
+} // namespace doc
diff --git a/src/doc/render_plan.h b/src/doc/render_plan.h
new file mode 100644
index 000000000..358eddf2f
--- /dev/null
+++ b/src/doc/render_plan.h
@@ -0,0 +1,42 @@
+// Aseprite Document Library
+// Copyright (c) 2023  Igara Studio S.A.
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifndef DOC_RENDER_PLAN_H_INCLUDED
+#define DOC_RENDER_PLAN_H_INCLUDED
+#pragma once
+
+#include "doc/cel_list.h"
+#include "doc/frame.h"
+
+namespace doc {
+  class Layer;
+
+  // Creates a list of cels to be rendered in the correct order
+  // (depending on layer ordering + z-index) to render the given root
+  // layer/layers.
+  class RenderPlan {
+  public:
+    RenderPlan();
+
+    const CelList& cels() const {
+      if (m_processZIndex)
+        processZIndexes();
+      return m_cels;
+    }
+
+    void addLayer(const Layer* layer,
+                  const frame_t frame);
+
+  private:
+    void processZIndexes() const;
+
+    mutable CelList m_cels;
+    mutable bool m_processZIndex = true;
+  };
+
+} // namespace doc
+
+#endif
diff --git a/src/doc/render_plan_tests.cpp b/src/doc/render_plan_tests.cpp
new file mode 100644
index 000000000..194a96b3e
--- /dev/null
+++ b/src/doc/render_plan_tests.cpp
@@ -0,0 +1,98 @@
+// Aseprite Document Library
+// Copyright (c) 2023  Igara Studio S.A.
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gtest/gtest.h>
+
+#include "doc/render_plan.h"
+
+#include "doc/cel.h"
+#include "doc/document.h"
+#include "doc/image.h"
+#include "doc/layer.h"
+#include "doc/sprite.h"
+
+#include <memory>
+
+using namespace doc;
+
+#define HELPER_LOG(a, b) \
+  a->layer()->name() << " instead of " << b->layer()->name()
+
+#define EXPECT_PLAN(a, b, c, d)                                         \
+  {                                                                     \
+    RenderPlan plan;                                                    \
+    plan.addLayer(spr->root(), 0);                                      \
+    const auto& cels = plan.cels();                                     \
+    EXPECT_EQ(a, cels[0]) << HELPER_LOG(cels[0], a);                    \
+    EXPECT_EQ(b, cels[1]) << HELPER_LOG(cels[1], b);                    \
+    EXPECT_EQ(c, cels[2]) << HELPER_LOG(cels[2], c);                    \
+    EXPECT_EQ(d, cels[3]) << HELPER_LOG(cels[3], d);                    \
+  }
+
+TEST(RenderPlan, ZIndex)
+{
+  auto doc = std::make_shared<Document>();
+  ImageSpec spec(ColorMode::INDEXED, 2, 2);
+  Sprite* spr;
+  doc->sprites().add(spr = Sprite::MakeStdSprite(spec));
+
+  LayerImage
+    *lay0 = static_cast<LayerImage*>(spr->root()->firstLayer()),
+    *lay1 = new LayerImage(spr),
+    *lay2 = new LayerImage(spr),
+    *lay3 = new LayerImage(spr);
+
+  lay0->setName("a");
+  lay1->setName("b");
+  lay2->setName("c");
+  lay3->setName("d");
+
+  Cel* a = lay0->cel(0),
+    *b, *c, *d;
+  lay1->addCel(b = new Cel(0, ImageRef(Image::create(spec))));
+  lay2->addCel(c = new Cel(0, ImageRef(Image::create(spec))));
+  lay3->addCel(d = new Cel(0, ImageRef(Image::create(spec))));
+
+  spr->root()->insertLayer(lay1, lay0);
+  spr->root()->insertLayer(lay2, lay1);
+  spr->root()->insertLayer(lay3, lay2);
+
+  a->setZIndex(0); EXPECT_PLAN(a, b, c, d);
+  a->setZIndex(1); EXPECT_PLAN(b, a, c, d);
+  a->setZIndex(2); EXPECT_PLAN(b, c, a, d);
+  a->setZIndex(3); EXPECT_PLAN(b, c, d, a);
+  a->setZIndex(4); EXPECT_PLAN(b, c, d, a);
+  a->setZIndex(1000); EXPECT_PLAN(b, c, d, a);
+  a->setZIndex(0); EXPECT_PLAN(a, b, c, d); // Back no normal
+
+  b->setZIndex(-1); EXPECT_PLAN(b, a, c, d);
+  b->setZIndex(-2); EXPECT_PLAN(b, a, c, d);
+  b->setZIndex(-3); EXPECT_PLAN(b, a, c, d);
+  b->setZIndex(-1000); EXPECT_PLAN(b, a, c, d);
+  b->setZIndex(0); EXPECT_PLAN(a, b, c, d); // Back no normal
+
+  a->setZIndex(-1);
+  b->setZIndex(-1);
+  c->setZIndex(-1);
+  d->setZIndex(-1);
+  EXPECT_PLAN(a, b, c, d);
+
+  a->setZIndex(2);
+  b->setZIndex(-1);
+  c->setZIndex(0);
+  d->setZIndex(-1);
+  EXPECT_PLAN(b, d, c, a);
+}
+
+int main(int argc, char** argv)
+{
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/src/doc/sprite.cpp b/src/doc/sprite.cpp
index 156c72f56..d02d62afe 100644
--- a/src/doc/sprite.cpp
+++ b/src/doc/sprite.cpp
@@ -22,6 +22,7 @@
 #include "doc/palette.h"
 #include "doc/primitives.h"
 #include "doc/remap.h"
+#include "doc/render_plan.h"
 #include "doc/rgbmap_rgb5a3.h"
 #include "doc/tag.h"
 #include "doc/tilesets.h"
@@ -624,22 +625,16 @@ void Sprite::remapTilemaps(const Tileset* tileset,
 //////////////////////////////////////////////////////////////////////
 // Drawing
 
-void Sprite::pickCels(const double x,
-                      const double y,
-                      const frame_t frame,
+void Sprite::pickCels(const gfx::PointF& pos,
                       const int opacityThreshold,
-                      const LayerList& layers,
+                      const RenderPlan& plan,
                       CelList& cels) const
 {
-  gfx::PointF pos(x, y);
-
-  for (int i=(int)layers.size()-1; i>=0; --i) {
-    const Layer* layer = layers[i];
-
-    Cel* cel = layer->cel(frame);
-    if (!cel)
-      continue;
-
+  // Iterate cels in reversed order (from the front-most to the
+  // bottom-most) so we pick first visible cel in the given position.
+  const CelList& planCels = plan.cels();
+  for (auto it=planCels.rbegin(), end=planCels.rend(); it!=end; ++it) {
+    Cel* cel = *it;
     const Image* image = cel->image();
     if (!image)
       continue;
@@ -752,6 +747,11 @@ CelsRange Sprite::cels(frame_t frame) const
   return CelsRange(this, selFrames);
 }
 
+CelsRange Sprite::cels(const SelectedFrames& selFrames) const
+{
+  return CelsRange(this, selFrames, CelsRange::ALL);
+}
+
 CelsRange Sprite::uniqueCels() const
 {
   SelectedFrames selFrames;
diff --git a/src/doc/sprite.h b/src/doc/sprite.h
index 2eda4fdcd..a91d7fde3 100644
--- a/src/doc/sprite.h
+++ b/src/doc/sprite.h
@@ -36,7 +36,6 @@
 #define DOC_SPRITE_MAX_HEIGHT 65535
 
 namespace doc {
-
   class CelsRange;
   class Document;
   class Image;
@@ -46,6 +45,7 @@ namespace doc {
   class Mask;
   class Palette;
   class Remap;
+  class RenderPlan;
   class RgbMap;
   class RgbMapRGB5A3;
   class SelectedFrames;
@@ -197,11 +197,9 @@ namespace doc {
     void remapImages(const Remap& remap);
     void remapTilemaps(const Tileset* tileset,
                        const Remap& remap);
-    void pickCels(const double x,
-                  const double y,
-                  const frame_t frame,
+    void pickCels(const gfx::PointF& pos,
                   const int opacityThreshold,
-                  const LayerList& layers,
+                  const RenderPlan& plan,
                   CelList& cels) const;
 
     ////////////////////////////////////////
@@ -214,6 +212,7 @@ namespace doc {
 
     CelsRange cels() const;
     CelsRange cels(frame_t frame) const;
+    CelsRange cels(const SelectedFrames& selFrames) const;
     CelsRange uniqueCels() const;
     CelsRange uniqueCels(const SelectedFrames& selFrames) const;
 
diff --git a/src/render/CMakeLists.txt b/src/render/CMakeLists.txt
index 748f08e71..9e06f22ab 100644
--- a/src/render/CMakeLists.txt
+++ b/src/render/CMakeLists.txt
@@ -1,5 +1,5 @@
 # Aseprite Render Library
-# Copyright (C) 2019  Igara Studio S.A.
+# Copyright (C) 2019-2023  Igara Studio S.A.
 # Copyright (C) 2001-2018 David Capello
 
 add_library(render-lib
diff --git a/src/render/render.cpp b/src/render/render.cpp
index c89211c9a..ec1afc3a9 100644
--- a/src/render/render.cpp
+++ b/src/render/render.cpp
@@ -17,6 +17,7 @@
 #include "doc/image_impl.h"
 #include "doc/layer_tilemap.h"
 #include "doc/playback.h"
+#include "doc/render_plan.h"
 #include "doc/tileset.h"
 #include "doc/tilesets.h"
 #include "gfx/clip.h"
@@ -679,8 +680,11 @@ void Render::renderLayer(
     return;
 
   m_globalOpacity = 255;
-  renderLayer(
-    layer, dstImage, area,
+
+  doc::RenderPlan plan;
+  plan.addLayer(layer, frame);
+  renderPlan(
+    plan, dstImage, area,
     frame, compositeImage,
     true, true, blendMode, false);
 }
@@ -772,18 +776,21 @@ void Render::renderSprite(
 }
 
 void Render::renderSpriteLayers(Image* dstImage,
-                              const gfx::ClipF& area,
-                              frame_t frame,
-                              CompositeImageFunc compositeImage)
+                                const gfx::ClipF& area,
+                                frame_t frame,
+                                CompositeImageFunc compositeImage)
 {
+  doc::RenderPlan plan;
+  plan.addLayer(m_sprite->root(), frame);
+
   // Draw the background layer.
   m_globalOpacity = 255;
-  renderLayer(m_sprite->root(), dstImage,
-              area, frame, compositeImage,
-              true,
-              false,
-              BlendMode::UNSPECIFIED,
-              false);
+  renderPlan(plan, dstImage,
+             area, frame, compositeImage,
+             true,
+             false,
+             BlendMode::UNSPECIFIED,
+             false);
 
   // Draw onion skin behind the sprite.
   if (m_onionskin.position() == OnionskinPosition::BEHIND)
@@ -791,11 +798,11 @@ void Render::renderSpriteLayers(Image* dstImage,
 
   // Draw the transparent layers.
   m_globalOpacity = 255;
-  renderLayer(m_sprite->root(), dstImage,
-              area, frame, compositeImage,
-              false,
-              true,
-              BlendMode::UNSPECIFIED, false);
+  renderPlan(plan, dstImage,
+             area, frame, compositeImage,
+             false,
+             true,
+             BlendMode::UNSPECIFIED, false);
 }
 
 void Render::renderBackground(Image* image,
@@ -890,8 +897,10 @@ void Render::renderOnionskin(
         else if (m_onionskin.type() == OnionskinType::RED_BLUE_TINT)
           blendMode = (frameOut < frame ? BlendMode::RED_TINT: BlendMode::BLUE_TINT);
 
-        renderLayer(
-          onionLayer, dstImage,
+        doc::RenderPlan plan;
+        plan.addLayer(onionLayer, frameIn);
+        renderPlan(
+          plan, dstImage,
           area, frameIn, compositeImage,
           // Render background only for "in-front" onion skinning and
           // when opacity is < 255
@@ -986,8 +995,8 @@ void Render::renderImage(
     m_newBlendMethod);
 }
 
-void Render::renderLayer(
-  const Layer* layer,
+void Render::renderPlan(
+  RenderPlan& plan,
   Image* image,
   const gfx::Clip& area,
   const frame_t frame,
@@ -997,185 +1006,176 @@ void Render::renderLayer(
   const BlendMode blendMode,
   bool isSelected)
 {
-  // we can't read from this layer
-  if (!layer->isVisible())
-    return;
+  for (const Cel* cel : plan.cels()) {
+    const Layer* layer = cel->layer();
 
-  if (m_selectedLayerForOpacity == layer)
-    isSelected = true;
+    ASSERT(layer->isVisible()); // Hidden layers shouldn't be in the plan
 
-  const Cel* cel = nullptr;
-  gfx::Rect extraArea;
-  bool drawExtra = false;
+    if (m_selectedLayerForOpacity == layer)
+      isSelected = true;
 
-  if (m_extraCel &&
-      m_extraImage &&
-      layer == m_currentLayer &&
-      ((layer->isBackground() && render_background) ||
-       (!layer->isBackground() && render_transparent)) &&
-      // Don't use a tilemap extra cel (IMAGE_TILEMAP) in a
-      // non-tilemap layer (in the other hand tilemap layers allow
-      // extra cels of any kind). This fixes a crash on renderCel()
-      // when we were painting the Preview window using a tilemap
-      // extra image to patch a regular layer, when switching from a
-      // tilemap layer to a regular layer.
-      ((layer->isTilemap()) ||
-       (!layer->isTilemap() && m_extraImage->pixelFormat() != IMAGE_TILEMAP))) {
-    if (frame == m_extraCel->frame() &&
-        frame == m_currentFrame) { // TODO this double check is not necessary
-      drawExtra = true;
-    }
-    else {
-      // Check if we can draw the extra cel when we render a linked
-      // frame.
-      cel = layer->cel(frame);
-      Cel* cel2 = layer->cel(m_extraCel->frame());
-      if (cel && cel2 &&
-          cel->data() == cel2->data()) {
+    gfx::Rect extraArea;
+    bool drawExtra = false;
+
+    if (m_extraCel &&
+        m_extraImage &&
+        layer == m_currentLayer &&
+        ((layer->isBackground() && render_background) ||
+         (!layer->isBackground() && render_transparent)) &&
+        // Don't use a tilemap extra cel (IMAGE_TILEMAP) in a
+        // non-tilemap layer (in the other hand tilemap layers allow
+        // extra cels of any kind). This fixes a crash on renderCel()
+        // when we were painting the Preview window using a tilemap
+        // extra image to patch a regular layer, when switching from a
+        // tilemap layer to a regular layer.
+        ((layer->isTilemap()) ||
+         (!layer->isTilemap() && m_extraImage->pixelFormat() != IMAGE_TILEMAP))) {
+      if (frame == m_extraCel->frame() &&
+          frame == m_currentFrame) { // TODO this double check is not necessary
         drawExtra = true;
       }
-    }
-  }
-
-  if (drawExtra) {
-    extraArea = m_extraCel->bounds();
-    extraArea = m_proj.apply(extraArea);
-    if (m_proj.scaleX() < 1.0) extraArea.w--;
-    if (m_proj.scaleY() < 1.0) extraArea.h--;
-    if (extraArea.w < 1) extraArea.w = 1;
-    if (extraArea.h < 1) extraArea.h = 1;
-  }
-
-  switch (layer->type()) {
-
-    case ObjectType::LayerImage:
-    case ObjectType::LayerTilemap: {
-      if ((!render_background  &&  layer->isBackground()) ||
-          (!render_transparent && !layer->isBackground()))
-        break;
-
-      // Ignore reference layers
-      if (!(m_flags & Flags::ShowRefLayers) &&
-          layer->isReference())
-        break;
-
-      if (!cel)
+      else {
+        // Check if we can draw the extra cel when we render a linked
+        // frame.
         cel = layer->cel(frame);
-
-      if (cel) {
-        Palette* pal = m_sprite->palette(frame);
-        const Image* celImage = nullptr;
-        gfx::RectF celBounds;
-
-        // Is the 'm_previewImage' set to be used with this layer?
-        if (m_previewImage &&
-            checkIfWeShouldUsePreview(cel)) {
-          celImage = m_previewImage;
-          celBounds = gfx::RectF(m_previewPos.x,
-                                 m_previewPos.y,
-                                 m_previewImage->width(),
-                                 m_previewImage->height());
-        }
-        // If not, we use the original cel-image from the images' stock
-        else {
-          celImage = cel->image();
-          if (cel->layer()->isReference())
-            celBounds = cel->boundsF();
-          else
-            celBounds = cel->bounds();
+        Cel* cel2 = layer->cel(m_extraCel->frame());
+        if (cel && cel2 &&
+            cel->data() == cel2->data()) {
+          drawExtra = true;
         }
+      }
+    }
 
-        if (celImage) {
-          const LayerImage* imgLayer = static_cast<const LayerImage*>(layer);
-          BlendMode layerBlendMode =
-            (blendMode == BlendMode::UNSPECIFIED ?
-             imgLayer->blendMode():
-             blendMode);
+    if (drawExtra) {
+      extraArea = m_extraCel->bounds();
+      extraArea = m_proj.apply(extraArea);
+      if (m_proj.scaleX() < 1.0) extraArea.w--;
+      if (m_proj.scaleY() < 1.0) extraArea.h--;
+      if (extraArea.w < 1) extraArea.w = 1;
+      if (extraArea.h < 1) extraArea.h = 1;
+    }
 
-          ASSERT(cel->opacity() >= 0);
-          ASSERT(cel->opacity() <= 255);
-          ASSERT(imgLayer->opacity() >= 0);
-          ASSERT(imgLayer->opacity() <= 255);
+    switch (layer->type()) {
 
-          // Multiple three opacities: cel*layer*global (*nonactive-layer-opacity)
-          int t;
-          int opacity = cel->opacity();
-          opacity = MUL_UN8(opacity, imgLayer->opacity(), t);
-          opacity = MUL_UN8(opacity, m_globalOpacity, t);
-          if (!isSelected && m_nonactiveLayersOpacity != 255)
-            opacity = MUL_UN8(opacity, m_nonactiveLayersOpacity, t);
+      case ObjectType::LayerImage:
+      case ObjectType::LayerTilemap: {
+        if ((!render_background  &&  layer->isBackground()) ||
+            (!render_transparent && !layer->isBackground()))
+          break;
 
-          // Generally this is just one pass, but if we are using
-          // OVER_COMPOSITE extra cel, this will be two passes.
-          for (int pass=0; pass<2; ++pass) {
-            // Draw parts outside the "m_extraCel" area
-            if (drawExtra && m_extraType == ExtraType::PATCH) {
-              gfx::Region originalAreas(area.srcBounds());
-              originalAreas.createSubtraction(
-                originalAreas, gfx::Region(extraArea));
+        // Ignore reference layers
+        if (!(m_flags & Flags::ShowRefLayers) &&
+            layer->isReference())
+          break;
 
-              for (auto rc : originalAreas) {
-                renderCel(
-                  image, cel, celImage, layer, pal, celBounds,
-                  gfx::Clip(area.dst.x+rc.x-area.src.x,
-                            area.dst.y+rc.y-area.src.y, rc),
-                  compositeImage, opacity, layerBlendMode);
-              }
-            }
-            // Draw the whole cel
-            else {
-              renderCel(
-                image, cel, celImage, layer, pal,
-                celBounds, area, compositeImage,
-                opacity, layerBlendMode);
-            }
+        if (!cel)
+          cel = layer->cel(frame);
 
-            if (m_extraType == ExtraType::OVER_COMPOSITE &&
-                layer == m_currentLayer &&
-                pass == 0) {
-              // Go for second pass with the extra blend mode...
-              layerBlendMode = m_extraBlendMode;
-            }
+        if (cel) {
+          Palette* pal = m_sprite->palette(frame);
+          const Image* celImage = nullptr;
+          gfx::RectF celBounds;
+
+          // Is the 'm_previewImage' set to be used with this layer?
+          if (m_previewImage &&
+              checkIfWeShouldUsePreview(cel)) {
+            celImage = m_previewImage;
+            celBounds = gfx::RectF(m_previewPos.x,
+                                   m_previewPos.y,
+                                   m_previewImage->width(),
+                                   m_previewImage->height());
+          }
+          // If not, we use the original cel-image from the images' stock
+          else {
+            celImage = cel->image();
+            if (cel->layer()->isReference())
+              celBounds = cel->boundsF();
             else
-              break;
+              celBounds = cel->bounds();
+          }
+
+          if (celImage) {
+            const LayerImage* imgLayer = static_cast<const LayerImage*>(layer);
+            BlendMode layerBlendMode =
+              (blendMode == BlendMode::UNSPECIFIED ?
+               imgLayer->blendMode():
+               blendMode);
+
+            ASSERT(cel->opacity() >= 0);
+            ASSERT(cel->opacity() <= 255);
+            ASSERT(imgLayer->opacity() >= 0);
+            ASSERT(imgLayer->opacity() <= 255);
+
+            // Multiple three opacities: cel*layer*global (*nonactive-layer-opacity)
+            int t;
+            int opacity = cel->opacity();
+            opacity = MUL_UN8(opacity, imgLayer->opacity(), t);
+            opacity = MUL_UN8(opacity, m_globalOpacity, t);
+            if (!isSelected && m_nonactiveLayersOpacity != 255)
+              opacity = MUL_UN8(opacity, m_nonactiveLayersOpacity, t);
+
+            // Generally this is just one pass, but if we are using
+            // OVER_COMPOSITE extra cel, this will be two passes.
+            for (int pass=0; pass<2; ++pass) {
+              // Draw parts outside the "m_extraCel" area
+              if (drawExtra && m_extraType == ExtraType::PATCH) {
+                gfx::Region originalAreas(area.srcBounds());
+                originalAreas.createSubtraction(
+                  originalAreas, gfx::Region(extraArea));
+
+                for (auto rc : originalAreas) {
+                  renderCel(
+                    image, cel, celImage, layer, pal, celBounds,
+                    gfx::Clip(area.dst.x+rc.x-area.src.x,
+                              area.dst.y+rc.y-area.src.y, rc),
+                    compositeImage, opacity, layerBlendMode);
+                }
+              }
+              // Draw the whole cel
+              else {
+                renderCel(
+                  image, cel, celImage, layer, pal,
+                  celBounds, area, compositeImage,
+                  opacity, layerBlendMode);
+              }
+
+              if (m_extraType == ExtraType::OVER_COMPOSITE &&
+                  layer == m_currentLayer &&
+                  pass == 0) {
+                // Go for second pass with the extra blend mode...
+                layerBlendMode = m_extraBlendMode;
+              }
+              else
+                break;
+            }
           }
         }
+        break;
       }
-      break;
+
+      case ObjectType::LayerGroup:
+        ASSERT(false);
+        break;
+
     }
 
-    case ObjectType::LayerGroup: {
-      for (const Layer* child : static_cast<const LayerGroup*>(layer)->layers()) {
-        renderLayer(
-          child, image,
-          area, frame,
-          compositeImage,
-          render_background,
-          render_transparent,
-          blendMode,
-          isSelected);
+    // Draw extras
+    if (drawExtra && m_extraType != ExtraType::NONE) {
+      if (m_extraCel->opacity() > 0) {
+        renderCel(
+          image,
+          m_extraCel,
+          m_sprite,
+          m_extraImage,
+          m_currentLayer, // Current layer (useful to use get the tileset if extra cel is a tilemap)
+          m_sprite->palette(frame),
+          m_extraCel->bounds(),
+          gfx::Clip(area.dst.x+extraArea.x-area.src.x,
+                    area.dst.y+extraArea.y-area.src.y,
+                    extraArea),
+          m_extraCel->opacity(),
+          m_extraBlendMode);
       }
-      break;
-    }
-
-  }
-
-  // Draw extras
-  if (drawExtra && m_extraType != ExtraType::NONE) {
-    if (m_extraCel->opacity() > 0) {
-      renderCel(
-        image,
-        m_extraCel,
-        m_sprite,
-        m_extraImage,
-        m_currentLayer, // Current layer (useful to use get the tileset if extra cel is a tilemap)
-        m_sprite->palette(frame),
-        m_extraCel->bounds(),
-        gfx::Clip(area.dst.x+extraArea.x-area.src.x,
-                  area.dst.y+extraArea.y-area.src.y,
-                  extraArea),
-        m_extraCel->opacity(),
-        m_extraBlendMode);
     }
   }
 }
diff --git a/src/render/render.h b/src/render/render.h
index 621c4cb7f..78ee0e9e9 100644
--- a/src/render/render.h
+++ b/src/render/render.h
@@ -28,6 +28,7 @@ namespace doc {
   class Image;
   class Layer;
   class Palette;
+  class RenderPlan;
   class Sprite;
   class Tileset;
 }
@@ -158,8 +159,8 @@ namespace render {
       const frame_t frame,
       const CompositeImageFunc compositeImage);
 
-    void renderLayer(
-      const Layer* layer,
+    void renderPlan(
+      doc::RenderPlan& plan,
       Image* image,
       const gfx::Clip& area,
       const frame_t frame,
diff --git a/src/render/render_tests.cpp b/src/render/render_tests.cpp
index 351793e6a..9d25c0e9e 100644
--- a/src/render/render_tests.cpp
+++ b/src/render/render_tests.cpp
@@ -1,4 +1,4 @@
-// Aseprite Document Library
+// Aseprite Render Library
 // Copyright (c) 2019-2023 Igara Studio S.A.
 // Copyright (c) 2001-2018 David Capello
 //
diff --git a/tests/scripts/cel.lua b/tests/scripts/cel.lua
index c7ee77905..2894c5c2d 100644
--- a/tests/scripts/cel.lua
+++ b/tests/scripts/cel.lua
@@ -1,3 +1,4 @@
+-- Copyright (C) 2023  Igara Studio S.A.
 -- Copyright (C) 2018  David Capello
 --
 -- This file is released under the terms of the MIT license.
@@ -27,3 +28,11 @@ assert(c.data == "test")
 c.position = Point(2, 4)
 assert(c.position == Point(2, 4))
 assert(c.bounds == Rectangle(2, 4, 32, 64))
+
+assert(c.opacity == 255)
+c.opacity = 128
+assert(c.opacity == 128)
+
+assert(c.zIndex == 0)
+c.zIndex = -2
+assert(c.zIndex == -2)